Detonator



C. H.' ALLISON.

DETONATOR.

APPLICATION FILED JULY 18. I918.

Patented June 10, 1919.

cnnzanns n. nnnrson, or GLENDALE, canrromrm.

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Specification of Letters Patent.

Patented June Application filedJ'uly 18, 1918. Serial No. 245,507.

To all whom it may concern Be it known'that I, CHARLES H. ALLISON, acitizen of the United States, residing at Glendale, in the county of LosAngeles, State of California, have invented new and useful Improvementsin Detonators, of which the following is a specification.

This invention relates to detonators adapted for work under great waterpressure; and it is an object of thisinvention to provide a simple formof device for mechanically protecting a cap or detonator against waterpressure, or any other heavy pressure; and at the same time to providean organization in which detonation of the explosive charge is sure andeflicient. This invention relates generally to the subject matter ofdeep water blasting; to which my following mentioned patents alsorelate:

No. 1,094,692, date April 28, 1914. No. 1,163,965, date Dec. 14, 1015.No. 1,215,329, date Feb. 13,1917. No. 1,239,247, date Sept. 4, 1917.

In Patent No. 1,163,9 5 of Dec. 14, 1915,

I have described a protection which embodies an outer protective shelland a covering of plastic material around the cap or detonator; and inPatent No. 1,239,247 of caps and the end of a detonator fuse.

Sept. 4, 1917, I have described a cylindrical protective shell whichcontains a cap Tlor e present invention partakes somewhat of the natureof each of these previous inventions; but with the improvement that thepresent invention provides a meansfor effectively protecting the cap ordetonator by the strength of a surrounding casing, rather than by-anyother primary means; and at the same time provides an organization thatinsures effective detonation of the charge. It is an object of thepresent invention to provide a casing or container which will thoroughlyand efi'ectively mechanically protect the cap or detonator against waterpressure; to provide a container which is ex-.

ceedingly strong and at the -same time very simple in construction andeasy of manufacture; to provide, in combination with such a container, adetonating-organization which will give effective results; and toprovide particularly an organization which may be placed in a veryrestricted space. In connection with this last mentioned object it maybe here stated that it is very often desirable to make up ablasting-charge capable of passing through a string of rotary drillin-gtools. .For such purpose the tube holding the explosive charge must beas small as 19; diameter and the protected detonator must be smallenough to fit inside such a tube. I have in one of my former Patents,

No. 1,215,329, described one means of protecting acap in such a manneras to make the protected-cap of small diameter; but the present means 1sin its essentials an entirely mechanical means which protects the capby.

sheer strength. Ishall now roceed to a detailed description of a preerred form of device embodying my present invention,

reference for this purpose being had to the accompanying drawings, inwhich- Figure 1 is a longitudinal section greatly reduced showing ablasting charge made up in typical form; Fig. 2 is an exterior elevationapproximately of the normal, size of the protected cap or detonator;Fig. 3 is a longitudinal central section of the same; and Fig. 4 is across-section on line 44 of Fig.3.

In. the drawings I show a tubular container at 10 which may berelatively long and slender, provided with a cap 11 on its lower end anda bail 12 of an suitable kind upon its upper end. Into thls tubularcontainer 10 the explosive charge is placed preferablyin the form ofsticks ofgelatin.

as shown at 13. In a common form of device there may be first a stick ofgelatinplaced in the lower end of'the container and then one of myprotected detonators D; and

then one or more gelatin sticks; then another detonator -D with anotherstick of gelatin above it. This arrangement however maybe varied atwill. An igniting wire 15 extends down to the explosive charge, thiswire running alongside the suspension cable 15 which is attached to bail12. The igmting begrounded upon the tubular container 10.'

For convenience this ground may be made at the upper end of thecontainer.

Each protected detonator embodies the parts and the organization nowabout to be described. I employ a tubular shell 20', something over3 lonand about {5" external diameter; and, or a certain size of interiordetonating charge, interior di- 1 ameter. This shell is lplrefer'ably ofthe material known as hard ber. Such material withstands excessivelyheavy external pressure, being very strong in compression. Its strengthin tension may not be great enough to resist rupture when the containedcharge is detonated; but the strength is sufficient to more or lesseffectively direct the explosion longitudinally of the shell to blow outthe caps which close the ends. These caps are illustrated at 21 and theypreferably are made with reduced portions which enter the ends of theshell 20 a short distance, so that there is a shoulder at 22 which bearsagainst the end of the cylindrical shell. These caps are comparativelythick, and the shoulder 22 is of sufiicient area (the same as thecrosssectional area of the relatively thick tubular shell 20) to givethe caps a solid abutment against the ends of the shell so thatexcessive.

water pressure willnot force the cap into the shell. The reduced portionpro ecting into the ends. of the shell prevents displacement of the capsfrom their proper position. The caps are preferably of the same materialas the shell.

Inside the container formed by the tubular shell 20 and ca 21 I place adetonating organization ma e up of an-electric cap 23 and a charge ofsuch an explosive as trinitro-toluene, as shown at 24. I preferably makeup this organization by taking a piece of the .detonating fuse known ascordeau, which comprises a leaden tube 25 containing tri-nitro-toluene,and I remove enough of the explosive from the end of the short length ofcordeau to insert the electric cap 23 into one end of the lead tube. Onewire from the cap, as shown at 26, passes out through a passage hole 27in the adjacent closure cap'21. The lead wire 15 is brought down andmechanically connected to the detonator by windingaround a screw-eye 28screwed into theclosure cap 21; and the wire 26 is then twisted intoconnection with the lead wire 15. The other wire 29 which leads from theelectric cap is brought down alongside the lead tube 25, its insulationbeing removed so that the wire occupies a minimum space; and as the leadtube is very nearly as large as the bore of shell 20, more or less forcemust be applied to force the lead tube into the shell. This having beendone, the wires 26 and '29 are then passed through the closure caps, andthe closure caps put in place, a small amount of glue, shellac or thelike, being used to make a tight joint and to help hold the closure capagainst displacement. The Wires having been connected in the mannerdescribed, the whole body is then taped with some suitable tape, eitheran ordinary insulating tape or a rubber tape; so that it is then coveredwith an exterior protective taping as shown at 30. This taping isextended over the closure caps and screw-eyes 28 and somewhat over thewires 15 and 15 and the joints between these wires and wires 26 and 29.The whole may then be dipped in liquid asphalt or may be painted with ahydrocarbon paint. This covering has as its function as much the holdingof caps 21 in place as it has the making of the device water-tight. Thejoints between the closurecaps and the shell are essentially may have anefi'ect in aiding the direction of the explosion end-wise of the shell.

In order to protect holes 27 against the pressure, the taping may bemade somewhat heavier around the caps and over their ends and around thewires, etc.; and a heavier impregnation of asphalt used. But the wiresfit the holes '27 fairly tightly so that the taping cannot be forceddown into the holes by external pressure; and, if desired, the wires maybe surrounded by asphalt,- etc., which may be applied to the wires whenpassed through the caps and which may be applied to the ends of thecaps, around the wires, etc., before taping.

Having described a preferred form of my invention, I claim:

'1. A blasting organization comprising an elongated container, anexplosive charge in saidcontainer, and a detonator in said 0on tainerand arranged longitudinally thereof, .With one end adjacent theexplosive charge, said detonator comprising a tubular shell capable ofwithstanding heavy external pressure, a cap seated upon and closing theend of the shell next the explosive charge, said cap being shoulderedupon the shell and being of a strength to resist external pressure butrelatively easily removable from the shell by internal pressure, and anexplosive cap contained within the shell.

2. A blasting organization comprising an elongated container, charges ofexplosive material in said container, and a detonator placed between twoadjacent charges: and embodying a tubular shell placed longitudinally ofthe container with its ends adjacent the two adjacent explosive char 5,caps for the ends of said shell of suita le strength and shouldered upontheshell ends to resist external pressure, the shell being also capableof resisting external pressure, and the caps being relatively easilyremovable from the shell by internal pressure, and an explosive capcontained within the shell.

3. A detonator, embodying a tubular shell of relatively great strengthto resist internal and external pressure, a cap for the end of saidshell, being shouldered upon the shellv end and being relatively thickto withstand heavy external pressure but being relatively easilyremovable from the shell by internal pressure, and an explosive capwithin the shell.

4. A detonator, embodying a tubular shell of relatively great strengthto resist external pressure, caps for the ends of said shell, beingshouldered upon the shell ends and being relatively thick to withstandheavy external pressure but being relatively easily removable from theshell by internal pressure, a detonating charge within one end of theshell and an explosive cap contained in the other end of the shell.

5. A detonator, embodying a tubular shell explosive charge, a detonatorlying in proximlty to said charge with an end toward said char e, saiddetonator comprising a shell capa 1e of withstanding heavy internalpressure, a capping means-for the end of the shell adjacent the charge,said capping means being relatively freely removable from the shell byinterior pressure, and an explosive cap contained within the shell.

'7. In a. detonator, a tubular shell of relatively great strength toresist internal pressure, a cap for the end of the shell relativelyeasily removable therefrom byinternal pressure, a soft metal tube'fitting the interior of the shell, and an explosive cap fitted in thesoft metal tube.

8. In a detonator, a tubular shell of relatively great strength toresist internal pressure, a cap for the end of the shell relativelyeasily removable therefrom by internal pressure, a soft metal tubefitting the interior of the shell, and an explosive cap and an explosiveWithin the tube in end to end relation.

9. In a detonator, a tubular shell of relatively great strength toresist internal pressure, a soft metal tube fitting within the shell asa lining, and an explosive cap with in the tube.

. 10. In a detonator, a tubular shell of relatively great strength toresist internal pressure, a cap for the end of the shell relativelyeasily removable therefrom by internal pressure, a soft metal tubefitting the interior of the shell as a lining, said tube extending substantially the whole length of the interior of theshell and endingsubstantially against the cap, and an explosive cap-within the tube.

11. In a detonator, a tubular shell of relatively great strength toresist pressure, a cap for the end of the shell relatively easilyremovable therefrom by internal pressure and set upon the shell towithstand relatively great external ressure, and an explosive capcontained within the shell.

In witness that I claim the foregoing I have hereunto subscribed my namethis 10th day of July 1918.

CHARLES H. ALLISON.

